Pneumatic ball valve seal damage process and phenomenon

in high temperature and high pressure pneumatic ball valve ( 。 MPa saturated steam) , the trial process, and found a seal seat is damaged, the damaged seal seat, as shown. Through careful observation, found damaged media imported seal seat, the damaged part is the same, and the outlet seal intact. Want to make sure that in the process of seal seat in the process of the pneumatic valve opened or closed damaged, special points ball was tested. First of all, pneumatic ball valve is closed, resulting in saturated steam. MPa, preheating minutes, open the pneumatic valve, then check that the seal damaged; And then in turn, access to. MPa saturated steam, preheat minutes, close the pneumatic valve, then check that the seal seat is damaged, the results of two test import seal seat damage phenomenon. Due to the floating ball pneumatic valve sealing pressure of the medium under the principle of pneumatic valve structure, the pressure at the outlet seal seat in a certain range of displacement, so as to ensure the seal, so the import seal seat is damaged, not affect the sealing performance, the ball has certain concealment. When the pneumatic valve opening and closing action a few times, imports will partially damaged, the damage loss decrease in seal seat.

damage the seal seat damage of parts, on the basis of the consistency of the sealing seat and the opening and closing ceremonies will take place on the import side sealing damaged the same parts, pneumatic valves open and close the detailed analysis of the process.
as in figure a, when the ball is in close state, in the press displacement of the ball in some of the pressure at the outlet seal seat, show, by the outlet seal seat, to ensure that the pneumatic valve seal. And imported seal seat backward areas, to seal the bottom smaller than reduce, into the medium pressure seal at the bottom of the seat, press, sealing surface contact with the ball all the sealing seat at this time will not be damaged, when the pneumatic valves open operations ( Figure b) , imported pneumatic valve A and B of the central cavity cavity flows form A pressure difference delta p, when the flow from contact with the ball and pneumatic seat under this part of the pneumatic valve seat will lose support pressure, bending deformation in the medium term. When the ball continue to roll, the channel on the edge of the seal of the bending part will be crushed and sealing performance.
pneumatic valve closing process is the same. As shown in figure a, when the pneumatic valve opens, the load and nonmetal sealing seat ( Much bigger non-metallic expansion ratio coefficient of expansion coefficient of metal) Thermal expansion of the role of the pneumatic valve components, so the channel B cannot enter pneumatic valve cavity, so the central channel and B chamber pneumatic valve has a pressure difference delta P, but when the seal pneumatic valve seat sealing surface contact with all not deformation, sealed ball, the ball pneumatic valve closing ( As shown in figure b) , sphere and B channels have a cavity in the process of pressure balance, from the article to the B in the cavity, when the flow is in contact with the pneumatic valve seat, this seat part of the pressure loss under the support of the media, the bending deformation. This kind of distortion can occur in the ICONS on the may also occur in the lower left corner and the bottom right hand corner, entry seal seat is damaged, because when continue to close the pneumatic valves to figure c, the cavity between the location of the cavity and B, B, the cavity between the and c chamber to produce A pressure difference delta P, A and B of the chamber between the imported pneumatic seat delta P, make the pressure difference between the bending deformation is more serious, B and c ventricular is between the two countries, in this way, the deformation of the seal seat is fixed, when the ball into the edge of the curved fairway seal seat will be part of the crushing pressure difference, and export seal seat won't damaged.